1:1 FSB : Ram ratio. Is it necessary for Q9550?

[hohyss]

Hello everyone. This is my first post at toms hardware.

I am currently trying to get Q9550 Yorkfield and 8GB of RAM ( ddr 6400 ).

I;ve heard that 1:1 ratio is necessary to maximize your performance.

I have few questions regarding this issue.


1. When not overclocking

FSB of Q9550 at the stock setting ( I believe its around 333mhz )
is not equal to ddr 6400 ( 400mhz)

Do I have to adjust the fsb or ram to make it equal to 1:1 despite the
fact that im not overclocking it?


2. When Overclocking

Ive seen some post where people have 4:5 ratio or 5:4. What will be the performance difference for not having 1:1 ratio? 20%-40%?
Is 1:1 ratio really necessary?

3. Is Q9550 capable for OC?

Im not sure whether q9550 is a good cpu for overclocking. Looks like I have to go all the way up to 400mhz ( 3.4ghz). Is it possible on stock cooler or should I get an aftermarket cooler like arctic freezer 7 pro?

 

[jimmysmitty]

A 1:1 ratio is optimal for stability. Right now it would be at 667MHz for a 1:1. But if you go to say a 800MHz memory you will run it at a higher ratio and that normally allows for a bit better performance at the loss of stability.

 

[sportsfanboy]

There's lots of reasons for running 1:1... One is less stress on the motherboard because it doesn't have to deal with dividers. Two is generally lower latency, because when you go through a divider, you take a memory performance hit, but I don't think it is 20 to 40%. For example, no one with ddr3 1333 ram , are running 1:1. You would need a fsb of 666mhz, just isn't achievable with today's hardware. I wouldn't worry about getting 1:1, if you do great, if not, don't worry about it.

What I like to do is play around with frequency, timings, and dividers, until I get the lowest memory latency in Everest.

Optimizing an overall overclock, and particularly the memory, is all about settings, than testing the settings for stability and speed.

That cpu can make it to 3.4 no problem on a decent mobo, however the temperatures may be a little high with stock cooler.

 

[Vertigon]

"For example, no one with ddr3 1333 ramhttp://en.wikipedia.org/wiki/Ram , are running 1:1. You would need a fsbhttp://en.wikipedia.org/wiki/FSB of 666mhz, just isn't achievable with today's hardware."

huh?

 

[jimmysmitty]

^Thtas funny considering Iam runnin a 1:1 FSB with my memory on a 333MHz FSB x 4 @ 1333MHz. And CPU-Z states it too.

 

[Vertigon]

That's impossible jimmy, sportsfanboy said so lol

 

[uguv]

Yeah but that just means your ram is running at DDR2 667 speeds. He said nobody runs ram at 1333 speeds at 1:1 because it would take a 667mhz FSB.

 

[sportsfanboy]

Guys, DDR2 800mhz requires a fsb of 400mhz to get 1:1!

DDR2 1000mhz requires a fsb of 500mhz to run 1:1!

DDR2 1200mhz requires a fsb of 600mhz to run 1:1!

DDR3 1333mhz requires a fsb of 666 to run 1:1!

Get your head out of your azzes before giving me crap, I'm right

 

[Grimmy]

Um.. the missing key word is rated fsb. 😛

 

[hohyss]

So I guess I should go with Q9550 and ddr 6400 ( ddr 800mhz ) +Artic cooling freezer 7 pro ( just to be safe )
then overclock it all the way to 3.4 gbz so i can have 1:1 ratio with ddr 800

I hope this combination is good. And btw I don't have to buy any thermal compound since artic cooling freezer 7 pro comes with preapplied grease. Right?

 

[Grimmy]

Guys, DDR2 800mhz requires a fsb of 400mhz to get 1:1!

DDR2 1000mhz requires a fsb of 500mhz to run 1:1!

DDR2 1200mhz requires a fsb of 600mhz to run 1:1!

DDR3 1333mhz requires a fsb of 666 to run 1:1!

Get your head out of your azzes before giving me crap, I'm right

Heh... I remember thinking the same thing.

Well, you can still run DDR800 at 533 for a 1:1 ratio. But for argument sake, yes @ advertised speed.

 

[uguv]

So I guess I should go with Q9550 and ddr 6400 ( ddr 800mhz ) +Artic cooling freezer 7 pro ( just to be safe )
then overclock it all the way to 3.4 gbz so i can have 1:1 ratio with ddr 800

I hope this combination is good. And btw I don't have to buy any thermal compound since artic cooling freezer 7 pro comes with preapplied grease. Right?

Well you have a few options:

1) You could leave the processor at stock speeds and by default your ram will run at DDR2 667 speeds. This wouldn't be the end of the world if you're not comfortable overclocking.

2) You could change the ratio and run your ram at DDR2 800 speeds but leave the processor at its stock speed. I probably wouldn't bother with this since if you're already messing around in the BIOS you might as well overclock the processor. 😉

3) Do as you say and overclock the processor so that it uses a 400mhz (x4) fsb. This would allow the ram to run at DDR2 800 with a 1:1 ratio.

4) Overclock the processor as far as you can and overclock the ram as well.

Personally I'd go with option 1 or 3.

Edit: nice info there, Computronix. I swear your post was originally above mine but moved somehow!

 

[sportsfanboy]

You can Grimmy, but I think the op was talking about maximizing his ram and trying for a 1:1 ratio without having to down clock his ram.

I always thought true 1:1 meant: FSB frequency x 2 = rams rated speed. So ddr2 800mhz should be 400mhz.

But you can run your system slower without a divider, however I believe the performance hit of seriously under clocking the ram, is greater than running it at full speed using a divider.

 

[CompuTronix]

Guys,

I posted the following on an earlier thread - http://www.tomshardware.com/forum/247906-29-ratio#t1765557

Ah, but wait... there's more! Let's consider some of the additional variables involved in the memory big picture: 😱

A ratio of 1:1 provides the best level of stability, since the memory controller, which is an integral part of the northbridge chipset for Intel processors, does not need to translate data flow across the FSB between the memory modules and the processor(s). Also, since memory and processor FSB clocks are synchronous at 1:1, (400:400 or DDR 800), there is no additional latency introduced.

If a minimal ratio of 4:5 (400:500 or DDR 1000) is used, then the resulting increase in memory frequency is effectivey cancelled out by the latency introduced in translation across the FSB between memory and processor clocks, and no increase in memory performance can be noticably detected in benchmarks. Also, asynchronous or mismatched clocks, create an element of potential instability within the memory controller, so depending on the chipset, an increase in northbridge and memory voltage is required for stability, which results in more heat, and less FSB overclock ceiling.

If a more aggressive ratio of 2:3 (400:600 or DDR 1200) is used, then the increase in memory frequency can marginally overcome the latency introduced in translation across the FSB between memory and processor clocks, resulting in a marginal increase in memory performance, which typically yields an increase in memory benchmarks of 2 to 3%, and is relatively negligible in terms of overall system performance.

In the case of expensive DDR3, where a ratio of 1:2 (400:800 or DDR 1600) or 2:5 (400:1000 or DDR 2000) is used, even with the tightest timings, an increase in memory benchmarks of only 3 to 4% is yielded over DDR2 800, which once again, is relatively negligible in terms of overall system performance. It's also noteworthy to consider that memory timings of 4-4-4-12 compared to 5-5-5-15, will yield an increase in memory benchmarks of less than 2%. However, for those of us who have the need for speed, we'll take whatever we can tweak.

Additionally, at equal specifications, 4 memory modules offer less FSB overclock ceiling than 2 modules, since more northbridge and memory voltage is required to maintain stability, and 4 slots require twice the current of 2 slots, again resulting in more heat, which typically is pulled into the CPU cooler, where it can increase processor temperatures by a few unwanted degrees.

I hope this helps to provides a greater degree of perspective (no pun intended). 😀

Comp

Incidentally, I run my rig at 1:1.

 

[sportsfanboy]

Man... I'm gonna shut up from now on, and let Computronix, do the dirty work.

Nice Comp

 

[CompuTronix]

Thanks sportsfanboy. I couldn't help but notice since you've been here at Tom's, that you know your stuff. It's always nice to have someone new aboard who can help us contribute to the Forums.

Keep up the good work!

Comp

 

[Vertigon]

Ladies and gentlemen why don't we stick to industry convention for the newbies sake.

Eg: An E8400 is 3Ghz and rated 1333 FSB

http://www.newegg.com/Product/Product.aspx?Item=N82E16819115037

RAM is available for said cpu, also rated at 1333 FSB

http://www.newegg.com/Product/Product.aspx?Item=N82E16820220278

Sure along the way there are things known as multipliers, clock cycles and quad pumping etc. If we chose to be silly about we could say our E8400 is really at 333 Mhz, along with our RAM at 333 Mhz, but we don't do we?

Like my friend might say "Wakey wakey, hand off snakey"

 

[Grimmy]

Umm Vertigon, you don't need DDR3 1333 to run the E8400. If your going to run it stock, DDR2 667 is all you really need.

667/ 2 (double rated) = 333.5

333.5 x 4 = 1333 rated FSB

333 x 9 = 3ghz CPU speed

That is as simple as I can put it.

Edit:

Which would be a 1:1 ratio.

 

[CompuTronix]

Vertigon,

I agree with Grimmy. Additionally, as I have no desire to spend hohyss's money for him, DDR3 motherboards and memory are still quite pricey, and aside from slightly lower memory power consumption and temperatures, the difference in performance is too small to justify DDR3 parts for a cost effective build.

The funds saved would be much more useful elsewhere.

 

[eklipz330]

HOLD ON ONE SECOND

i coulda SWORN ddr3 1333 was for a cpu speed of 333mhz

as ddr2 667 was for a cpu speed 333mhz

that's why ddr3 1600 is STANDARD for a cpu speed of 400mhz

im pretty sure of this guys... im gonna go link hunting

 

[sportsfanboy]

Vertigon here's a few lines from the above paragraphs

In the case of expensive DDR3 http://en.wikipedia.org/wiki/DDR3_SDRAM , where a ratio of 1:2 (400:800 or DDR 1600) or 2:5 (400:1000 or DDR 2000) is used, even with the tightest timings, an increase in memory benchmarks of only 3 to 4% is yielded over DDR2 http://en.wikipedia.org/wiki/DDR2_SDRAM 800, which once again, is relatively negligible in terms of overall system performance.

If money grows on trees, than ddr3 is ok ,however for most people it doesn't seem to make any practical sense to use ddr3 with the current platform.

 

[Grimmy]

DDR2-800 vs. DDR3-1333. Does DDR3-1333 Make Sense?

It can, but at the cost, for the example Vertigon had @ 180 bucks?

Edit:

I was going to put up the chart for memory speeds, but sportsfanboy beat me to it. :lol:

 

[sportsfanboy]

HOLD ON ONE SECOND

i coulda SWORN ddr3 1333 was for a cpu speed of 333mhz

as ddr2 667 was for a cpu speed 333mhz

that's why ddr3 1600 is STANDARD for a cpu speed of 400mhz

im pretty sure of this guys... im gonna go link hunting

Not at all close man...This is the math behind this shizil. FSB x Multiplyer=Cpu frequency, DDR2(double data rate) is FSB x2 (for double data rate)= effective ram speed with no divider.

So DDR2 1600 would need you to set a FSB of 800 in your bios in order to run 1:1

 

[eklipz330]

Not at all close man...This is the math behind this shizil. FSB x Multiplyer=Cpu frequency, DDR2(double data rate) is FSB x2 (for double data rate)= effective ram speed with no divider.

So DDR2 1600 would need you to set a FSB of 800 in your bios in order to run 1:1

omg are you serious lol im in disbelief

is this why nehalem doesn't use fsb?

 

[hohyss]

Vertigon,

Additionally, as I have no desire to spend hohyss's money for him..

lol.. dude...
I'd be quite suprised if stranger is willing to actually spend money on stranger. Just like I'd never be willing to spend a money on a you ;p jk

Btw will the price of core 2 duo/quad drop after Nehalem comes out? It seems like ddr 3 is way to expensive.and same goes for x58 mobo